高SiC含量的Al基复合材料的制备II:SiC预成形坯无压渗透纯Al

Fabrication of Aluminum Matrix Composites with High Volume Content of SiC II:Presureless Infiltration of Pure Aluminum into SiC Preforms

以氧化结合制备的SiC多孔骨架为先驱体,采用无压渗透工艺制备出致密、增强体分布高度均匀的纯铝基复合材料。SiC预成形坯渗入纯铝后无形状和尺寸的变化。加入SiC后,铝基体的强度提高至300MPa以上,弹性模量提高至120GPa以上且随SiC含量的增加而增大。复合材料的热膨胀性能可通过SiC的含量来调整,当SiC的体积含量介于39%至62%之间时,室温至100℃的平均线热膨胀系数介于12.9×10-6/℃至9.11×10-6/℃之间。

Compact SiC/Al composites with SiC particles uniformly distributing were fabricated by spontaneous infiltration of liquid pure aluminum into porous SiC preforms prepared by oxidation bonding process. Preforms have no change in shape and dimension after infiltration. The strength of pure aluminum matrix can be improved to beyond 300MPa as SiC particles added in. The elastic modulus of the composites beyond 120GPa increases with SiC volume fraction. The thermal expansion behavior of SiC/Al composites can be modulated by changing SiC fraction. The mean linear coefficient of thermal expansion （room temperature to 10022） ranges from 12.9 × 10^-6/22 to 9.11 × 10^-6/22 as SiC volume fraction ranging from 39% to 62%.